What's inside? - Mullard module 1402 - UK Vintage Radio Repair and Restoration Discussion Forum

rojosuiza · 8th Jun 2019, 11:24 am

My new Roberts R505 has good reception on AM; FM is rather weak.

Does anyone know, what hides inside the Mullard module 1402/02? - I can find a lot of guessing, but nobody seems to know...

Are there really AF11x transistors lurking in it?

HamishBoxer · 8th Jun 2019, 11:33 am

Very likely,I think.

TonyDuell · 8th Jun 2019, 1:02 pm

The manufacturer's service manual (available 'up top') includes the internals of this module on the full circuit diagram, but with no component values given.

It shows it contains a pair of NPN transistors, which I would think were unlikely to be AF11x's (or indeed germanium at all).

rojosuiza · 8th Jun 2019, 1:06 pm

I did see this on the service manual, no details about the transistors.

Maybe someone had a peek in the module though...

HamishBoxer · 8th Jun 2019, 1:18 pm

Apologies,I have the wrong Mullard module type.

paulsherwin · 8th Jun 2019, 1:39 pm

If they are NPN transistors then they are likely to be BF194/5 Lockfits.

rojosuiza · 8th Jun 2019, 1:49 pm

No AF11x then, no PNP

rojosuiza · 9th Jun 2019, 6:04 pm

We will not know what is inside the module, it seems, at least not for the time being.

What helps in the case of my radio is the proper voltage. The battery in my radio was quite tired I found out, when I eventually took the trouble to measure it.

Now the radio is connected to the power supply, the display says 8.93 Volts, 20 mA. All is well therefore: VHF also.

8th Jun 2019, 11:24 am	#1
rojosuiza Tetrode Join Date: Mar 2018 Location: Amsterdam, Netherlands Posts: 68	What's inside? - Mullard module 1402 My new Roberts R505 has good reception on AM; FM is rather weak. Does anyone know, what hides inside the Mullard module 1402/02? - I can find a lot of guessing, but nobody seems to know... Are there really AF11x transistors lurking in it?

8th Jun 2019, 11:33 am	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,931	Re: What's inside? - Mullard module 1402 Very likely,I think. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

8th Jun 2019, 1:02 pm	#3
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: What's inside? - Mullard module 1402 The manufacturer's service manual (available 'up top') includes the internals of this module on the full circuit diagram, but with no component values given. It shows it contains a pair of NPN transistors, which I would think were unlikely to be AF11x's (or indeed germanium at all).

8th Jun 2019, 1:06 pm	#4
rojosuiza Tetrode Join Date: Mar 2018 Location: Amsterdam, Netherlands Posts: 68	Re: What's inside? - Mullard module 1402 I did see this on the service manual, no details about the transistors. Maybe someone had a peek in the module though...

8th Jun 2019, 1:18 pm	#5
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,931	Re: What's inside? - Mullard module 1402 Apologies,I have the wrong Mullard module type. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

8th Jun 2019, 1:39 pm	#6
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,934	Re: What's inside? - Mullard module 1402 If they are NPN transistors then they are likely to be BF194/5 Lockfits.

8th Jun 2019, 1:49 pm	#7
rojosuiza Tetrode Join Date: Mar 2018 Location: Amsterdam, Netherlands Posts: 68	Re: What's inside? - Mullard module 1402 No AF11x then, no PNP

9th Jun 2019, 6:04 pm	#8
rojosuiza Tetrode Join Date: Mar 2018 Location: Amsterdam, Netherlands Posts: 68	Re: What's inside? - Mullard module 1402 We will not know what is inside the module, it seems, at least not for the time being. What helps in the case of my radio is the proper voltage. The battery in my radio was quite tired I found out, when I eventually took the trouble to measure it. Now the radio is connected to the power supply, the display says 8.93 Volts, 20 mA. All is well therefore: VHF also.